Ultrasound mediated synthesis of aldimines from non-enolizable aldehydes at room temperature

Abstract

A user-friendly, energy efficient method of synthesizing N-sulfonyl aldimines at room temperature (25‒28°C) from readily available and inexpensive reagents has been developed. The method employs ultrasonication from common laboratory ultrasonic cleaner to mediate the reaction. FeCl₃ as catalyst and molecular sieves as water scavenger have produced excellent yields of aldimines with short reaction time. The reaction set-up does not require inert atmosphere or anhydrous solvent thereby saving resources and time. The easily scalable method works well for the condensation of aromatic non-enolizable aldehydes and sulfonamides.